Side inlet means for centrifugal pumps

ABSTRACT

Side inlet means for a centrifugal pump has an inlet connected to the source of fluid to be pumped, and means forming a fluid flow passage extending through said side inlet means which defines, a diverging passage section, a shaped curved passage section, and a straight cylindrical passage section of varying length for delivering fluid to the suction eye of the impeller for the centrifugal pump having a velocity distribution which improves the efficiency thereof. Additionally, the side inlet means above described wherein the straight cylindrical passage section will have a predetermined length sufficient to permit operative association with inducer means for increasing the range of operation of the centrifugal pump.

United States Patent 1191 Yedidiah 1 Oct. 7, 1975 SIDE INLET MEANS FORCENTRIFUGAL PUMPS [75] Inventor: Shmariahu Yedidiah, West Orange,

[73] Assignee: Worthington Pump International,

Inc., Mountainside, NJ.

[22] Filed: June 27, 1973 [21] Appl. No.: 374,088

[52] US. Cl 415/182; 138/39 [51] Int. Cl. F04d 29/42; F04d 29/44 [58]Field of Search 415/182, 203, 206, 219, 415/204, 205; 417/360; 138/39[56] 7 References Cited UNlTED STATES PATENTS 1,215,451 2/1917 White60/696 2,303,949 12/1942 Nordell 2,433,156 12/1947 Pezzillom. 3,071,0751/1963 Spring 3,734,649 5/1971 Sandy 415/143 FOREIGN PATENTS ORAPPLICATIONS 727,357 6/1932 France 415/182 282,183 4/1952 Switzerland415/203 1,089,234 3/1955 France 415/203 1,033,425 7/1953 France1,035,385 8/1953 France 99,710 6/1923 Switzerland 138/39 PrimaryExaminer-William L. Freeh Assistant Examiner Louis J. CasaregolaAttorney, Agent, or FirmDaniel H. Bobis [57] ABSTRACT Side inlet meansfor a centrifugal pump has an inlet connected to the source of fluid tobe pumped, and means forming a fluid flow passage extending through saidside inlet means which defines, a diverging passage section, a shapedcurved passage section, and a straight cylindrical passage section ofvarying length for delivering fluid to the suction eye of the impellerfor the centrifugal pump having a velocity distribution which improvesthe efficiency thereof.

Additionally, the side inlet means above described wherein the straightcylindrical passage section will have a predetermined length sufficientto permit operative association with inducer means for increasing therange of operation of the centrifugal pump.

6 Claims, 18 Drawing Figures U.S. Patent Oct. 7,1975 Sheet 1 of23,910,715

Sheet 2 of 2 3,910,715

US. Patent Oct. 7,1975

63 FIG.\8

mmn.

SIDE INLET MEANS FOR CENTRIFUGAL PUNIPS BACKGROUND OF THE INVENTION Thisinvention relates generally to centrifugal pumps and more particularlyto a side inlet means for guiding delivery of fluid to be pumped intothe suction eye of the impeller for a centrifugal pump.

The efficiency of a centrifugal pump is affected by the characteristicsof the fluid delivered into the suction eye of the impeller for thepump. More specifically, the velocity. distribution of the fluid as itflows into the suction eye of the impeller should be maintained asuniform as possible to prevent cavitation and energy losses duringpumping of the fluid.

Where the-piping for passing fluid to be pumped leads directly into thesuction inlet for the casing so that the fluid runs through a straightflow passage for a given length of piping; these desirable conditionsfor the fluid entering the suction eye of the impeller can besubstantially achieved.

However, it is often desirable or necessary to connect pumps so that thefluid to be pumped is brought in through a side inlet means having aninlet in line with the piping arrangement for the system in which thepump is operating.

Such in line centrifugal pump arrangements are common because it permitsthe centrifugal pump to be positioned most advantageously in respect ofthe piping layoutfor the overall system. However, such side inlet Iconnection present problems in that it affects the function and theefficiency of the associate centrifugal pump connected thereto.

It has been found where the fluid to be pumped enters through a sideinlet means that an adverse velocity distribution develops because ofthe frictional losses through the side inlet means and the turningforces acting on the fluid as it flows to the suction eye of theimpeller for the centrifugal pump.

The known prior art side inlet means or connections deliver fluid to thesuction eye of the impeller for the centrifugal pump with a velocitydistribution which adversely affects the operation of the impeller inthat they cause fluid to be delivered to the impeller at conditions lessthan the design requirements and thus limit the range and capacity ofthe given pump and reduce the efficiency thereof.

One. form of adverse velocity distribution of the known prior art sideinlet means or connections is due to pre-rotation developed in the fluidentering the suction eye of the impeller. This is overcome in the priorart by various techniques. For example, a splitter fin or partition isinserted at a suitable point in the flow passage through the side inletmeans which construction increascs the cost of the pump.

Another means of meeting the pro-rotation developed in the fluidenteringthe suction eye of the impeller is to redesign the impeller to match ormeet the velocity distribution conditions of the fluid passing from theside inlet means to the suction eye of the impeller. This too isobjectionable because it requires the manufacturer to tool up andinventory different types of impellers for centrifugal pumps as afunction of the velocity distribution of the fluid entering the suctioneye of the impeller from either a straight piping line or a side inletmeans. t

The present invention overcomes these problems of the prior art devicesby providing a side inlet means or connection in which the fluid flowpassage therethrough is particularly designed to deliver fluid to bepumped to the suction eye of the impeller having a velocity distributionwhich produces a more efficient centrifugal pump operation and providesmeans to extend the range of operation of the pump.

This is accomplished by embodying between the inlet and the outlet forthe fluid flow passage through the side inlet means, an enteringdiverging section in communication with the inlet which expands from theinlet area to up to three times that of the outlet area so that thefluid will initially slow down or reduce its velocity, a sized andshaped intermediate section which gives a nozzle effect thus causes thefluid to accelerate to a velocity equal to or greater than its initialvelocity, and finally a straight cylindrical passage section just beforethe outlet through which the fluid to be pumped having a velocitydistribution which is more uniform than that obtainable by the knownprior art devices if passed to the suction eye of the impeller for theassociate centrifugal pump communicating with the outlet end of thefluid flow passage in the side inlet means.

The acceleration of the fluid through the sized and shaped intermediatesection produces the improved velocity distribution in the fluid passageto the suction eye of the impeller as above outlined.

SUMMARY OF THE INVENTION The present. invention provides an improvedside inlet means for centrifugal pumps in which the fluid flow passagetherein from the inlet to the outlet is characterized by a divergingpassage section from the inlet which expands at the end thereof remotefrom the inlet to a cross-sectional area up to three times the area atthe outlet and communicates with a sized and shaped curved passagesection which narrows at the end remote from the point of communicationwith the diverging passage section to a cross-section diameterapproximately equal to the diameter of the outlet and communicates withthe straight cylindrical passage section which forms the outlet at theremote end thereof for the fluid flow passage.

The side inlet means may be a separate element or may be formed integralwith the casing for the centrifugal pump and the straight cylindricalsection of the fluid flow passage may have a predetermined length toaccomodate an inducer means therein.

The construction of the present invention seeks to provide an improvedside inlet means for centrifugal pumps which will deliver fluid to thesuction eye of the impeller for the associated centrifugal pump at avelocity distribution which will improve the efficiency thereof.

It is another object of the present invention to provide a side inletmeans for centrifugal pumps which includes a fluid flow passagetherethrough having a straight cylindrical section immediately adjacentthe outlet end of the fluid flow passage which coacts with the remainingsections of the fluid flow passage to provide an improved velocitydistribution of the fluid delivered to the suction eye of the impellerfor the associated centrifugal pump and whichmay have a predeterminedlength sufficient for operative relation with an inducer means ,for thegiven centrifugal pump.

These and other objects and advantages of the invention and the variousfeatures and details thereof are hereinafter more fully described inconnection with the accompanying drawings in which:

FIG. 1 is a side elevation view of a motor driven pump with a side inletmeans in accordance with the invention.

FIG. 2 is an enlarged view partly in vertical section of the pump andside inlet means of the motor driven pump shown in FIG. 1.

FIG. 3 is a side elevation of the side inlet means shown in FIG. 1.

FIG. 4 is a top elevational view of the side inlet means shown in FIG.1.

FIG. 5 is an inlet end'view of the side inlet means shown in FIG. 1.

FIG. 6 is an outlet end view of the side inlet means shown in FIG. 1.

FIG. 7 is a horizontal section taken at line 77 of FIG. 3.

FIG. 8 is a section taken on line 88 of FIG. 7 illustrating the ovalwindow in the fluid flow passage of the side inlet means looking towardsthe outlet end of the fluid flow passage.

FIG. 9 is aside elevation of the motor driven pump shown in FIG. 7partly in vertical section showing an inducer element mounted inassociation with the straight cylindrical section of the fluid flow paththrough the side inlet connector.

FIG. 10 is a side elevation of a motor driven pump with an integralcasing and side inlet means in accordance with the invention.

FIG. 11 is an enlarged side view partly in vertical section of the motordriven pump with an integral casing and side inlet means as shown inFIG. 10.

FIG. 12 is a side elevational view of the integral casing and side inletmeans shown in FIG. 10.

FIG. 13 is a top elevational view of the integral casing and side inletmeans shown in FIG, 10.

FIG. 14 is an inlet end view of the integral casing and side inlet meansshown in FIG. 10.

FIG. 15 is an outlet view of the integral casing and side inlet meansshown in FIG. 10.

FIG. 16 is a horizontal section taken at line 1616 of FIG. 11.

FIG. 17 is a horizontal section taken at line 1717 of FIG. 1 1.

FIG. 18 is a side elevational view of the motor driven pump shown inFIG. 10 partly in vertical section having an inducer element mountedtherein in association with the straight cylindrical section of the sideinlet means section of the integral casing and side inlet means.

Referring to the drawings, FIG. 1 shows a motor driven centrifugal pump10 with a side inlet means 11 in accordance with the invention having aninlet 12 and outlet 13.

About the inlet 12 flange means 14 is provided for connecting the sideinlet means to a suitable conduit (not shown) communicating with thesource of the fluid to be pumped. Similarly, about the outlet 13, flangemeans 15 is provided having a plurality of circumferentially disposedopenings 16 through which threaded means 17 extend for connection tobores 18 provided in a boss 19 formed about the suction inlet 20 in thecasing 21 of the motor driven pump 10.

The casing 21 includes the conventional pumping chamber 22 incommunication with the suction inlet 20 and a discharge outlet 23 forpassing the fluid being pumped to any suitable point of use.

Mounted in the pumping chamber 22 is an impeller means 24 which isconnected and rotatable with the shaft 25 driven by the motor 26.

The impeller 24 is disposed in the pumping chamber 22 so that thesuction eye 27 is in direct communication with the suction inlet 20formed in the casing 21.

As can be readily seen from FIG. 2 of the drawings, the outlet 13 of theside inlet means 11 is in direct alignment with the suction inlet 20 andthe suction eye 27 of the impeller. Thus, fluid delivered to the suctioninlet 20 will flow directly into the suction eye 27 of the impeller 23for the centrifugal pump 10.

Fluid to be pumped is delivered from the inlet 12 to the outlet 13 ofthe side inlet means 11 by a fluid flow passage 30 therein having aparticular design hereinafter more fully described.

When the motor driven centrifugal pump 10 is in operation the fluid tobe pumped enters the inlet 12 and flows through the fluid flow passage30 to the outlet 13. By reason of the alignment of the outlet 13 withthe suction inlet 20 for the casing 21 and with the suction eye 27 forthe impeller 24, fluid will pass immediately into the rotating impeller24, where'it is discharged through the pumping chamber 22 to thedischarge outlet 23 for the centrifugal pump 10.

The operation of motor driven centrifugal pumps of the type shown in thepresent invention is so well understood by those skilled in the pumpingart that a further description of the illustrated pump is not deemednecessary for the purposes of the present invention which as noted aboveprovides for the advantageous results in design and arrangement byreason of the side inlet means and the fluid flow passage 30 therein nowto be more particularly described by reference to FIGS. 2 to 8 of thedrawings.

SIDE INLET MEANS Thus, referring to FIGS. 2 to 8, the side inlet meansshown is an elongated cylindrical or tubular member having convolutedcurved portions between the inlet 12 and the outlet 13 thereon.

Inlet 12 of the side inlet means 11 in assembled position is disposed ina plane above the outlet 13 substantially in alignment with thedischarged outlet 23.

Inlet 12 will be a spaced distance from casing 21 to permit the motordriven centrifugal pump 10 to be connected so that the inlet 12 and thedischarge outlet 23 will be in alignment with the piping conduit (notshown) for the pumping system in which the in line motor drivencentrifugal pump will be used. This particular configuration isillustrated because it is a desirable arrangement for a pumping system.It will be understood, however, that where the side inlet means 11 is aseparate element as shown in FIGS. 1 to 8 of the drawings, that is maybe positioned so that the inlet for the side inlet means 1 1 is at anydesired angle to the discharge outlet 23 of the centrifugal pump 10without departing from the scope of the present invention.

The side inlet means 11 has a descending section 31, a curved section 32and a straight cylindrical section 33. These sections of the side inletmeans contain the corresponding passage sections of the fluid flowpassage 30 which includes, diverging passage section 34, the shapedcurved passage section 35 and the straight cylindrical passage section36. These passage sections 34, 35 and 36 of the fluid flow passage 30communicate with each other in the order indicated from the inlet 12 tothe outlet 13. Thus, the inlet communicates with the diverging passagesection 34 which section is in communication with the shaped curvedpassage section 35, in turn in communication with the straightcylindrical passage section 36 which communicates with the outlet 13.

By reference to FIG. 2, the outlet 13 and the straight cylindricalpassage section 36 are shown in alignment with each other and as havingtheir centerline on the longitudinal or vertical line of the motordriven centrifugal pump 10.

Further, the outlet 13 and the straight cylindrical passage section 36are shown as having a diameter D. This diameter is the referencestandard from which the remaining portions of the fluid flow passage 30are designed. It may be equal to the diameter of the suction eye 27 ofthe impeller 24 as illustrated at FIG. 2 or may have a diameterdiffering from the preferred form illustrated up to greater or less thanthe diameter of the suction eye 27 without departing from the scope ofthe present invention.

In addition, FIG. 2 shows that the straight cylindrical passage section36 of the fluid flow passage 30 may have a predetermined length B. Thispredetermined length will be a function of the length of the inducer 40shown in assembled position in FIG. 8 of the drawings. However, exceptfor this operative relation, the length of the straight cylindricalpassage section 36 may be varied to provide operating results.

FIGS. 2 and 7 show that the inlet 12 will have a diameter A which may beslightly smaller, equal to or slightly larger than the diameter D of theoutlet 13. It should not be less than 0.75 of the diameter D andgenerally will be in the ratio 0.9 to 1.25 of the diameter D.

The diverging section 34 which communicates at one end with the inlet 12expands to a plane of communication with the shaped curved sectionpreferably in the form of an oval window or opening 37 which has a widthCW up to three times the diameter D and a height CH not less than 30% ofthe diameter of A whereby the total cross-sectional area of the ovalwindow or opening 37 will be in a range from 1.50 to 2.25 times thecross-section area of the outlet 13 and preferably will have a totalcross-section area in the range from 1.75 to 2.00 times thecross-sectional area of the outlet 13. It will be understood that theoval window or opening 37 is not an absolute limitation. Other shapescould be used without departing from the scope of the present invention.

From the point where the shaped curved passage section 35 communicatesat the plane of communication or oval window 37 with the divergingpassage section 34, it is curved on a radius substantially in range from0.75 to 1.50 of the diameter D of outlet 13. This radius is drawn on thecenterline of the side inlet means 1 1 at a point in alignment with theside of the straight cylindrical passage section 36 closest to the inlet12 for the side inlet means 11, as is clearly shown in FIGS. 4 and 7 ofthe drawings.

At the end remote from the oval window or opening 37 the shaped curvedpassage section 35 narrows to a cross-sectional area having a diametersubstantially equal to the diameter D so that the axial section thereofat the point which communicates with the straight cylindrical passagesection 36 is a smooth, uniform and simple bend.

Thus, there is provided a flow passage 30 from the inlet 12 to theoutlet 13 of the side inlet means which has a specific defined shape foraccomplishing the advantageous and desired result of providing fluidflow to the suction eye 22 of the impeller 24 of centrifugal pump 10having a substantially uniform velocity distribution.

COMBINED CASING AND SIDE INLET CONNECTOR In FIGS. 10 to 18 of thedrawings, an alternate form of motor driven centrifugal pump is shownhaving a side inlet means in accordance with the present inventioncombined with the casing of the pump portion of the motor drivencentrifugal pump.

Thus, FIGS. 10 and 11 show a motor driven, in line, centrifugal pump 50with a combined casing and side inlet means 51 having an inlet 52 and adischarge outlet 53 as is shown in FIG. 11 of the drawings.

It will be understood that while an in line centrifugal pump isillustrated that the combined casing and side inlet means can have theinlet and discharge outlet for the centrifugal pump at various angles toeach other other than the in line arrangement as shown without departingfrom the scope of the present invention.

About the inlet 52, a flange means 54 is provided for connecting thecombined casing and side inlet means 51 to a suitable conduit (notshown) communicating with the source of fluid to be pumped. Similarly,about the discharge outlet 53 a flange means 55 is provided with isconnected to suitable means (not shown) for passing the pumped fluidfrom the motor driven, in line, centrifugal pump 50 to any suitablepoint of use.

The combined casing and side inlet means 51 includes a casing section51a and a side inlet means section 51b and at the point 56 therein formsboth a suction inlet for the casing section 51a and an outlet for theside inlet section 51b which is referred to hereinafter as the suctioninlet/outlet 56 in the combined casing and side inlet means 51.

In the casing section 51a, a conventional pumping chamber 57 is formedwhich communicates with the suction inlet/outlet S6 to receive fluid tobe pumped from the side inlet means section 51b. Pumping chamber 57 alsocommunicates with the discharge outlet 53 for discharging fluid from thecentrifugal pump 50.

Mounted in the pumping chamber 57 is an impeller means 58 which isconnected and rotatable with a shaft 59 driven by the motor 60.

Impeller 58 is mounted in the pumping chamber 57 so that the suction eye61 is in direct communication with the suction inlet/outlet 56 formed atthe point where the casing section 51a and side inlet means section 51bare joined into integral unit form so that suction inlet/outlet 56 inthe combined casing and side inlet means 51 is thus in direct alignmentwith the suction eye 61 of the impeller 58.

Inlet 52 is in communication with the suction inlet/- outlet 57 by meansof a connecting passage 62.

When the motor driven, in line, centrifugal pump 50 is in operation, thefluid to be pumped enters the inlet 52, and flows through the connectingpassage 62 to the suction inlet/outlet 56. By reason of the alignment ofthe suction inlet/outlet 56 with the suction eye 61 of the impeller 58,fluid will pass immediately into the rotating impeller 58 where it isdischarged through pumping chamber 57 into the communicating dischargeoutlet 53 to the point of use.

The operation of motor driven centrifugal pumps of the type shown in thepresent invention are so well understood by those skilled in the artthat further description of the illustrated pump is not deemed necessaryfor the purposes of the present invention.

As in the form of the invention above described for FIGS. 1 to 8 of thedrawings, the connecting fluid flow passage 62 in the side inlet meanssection 51b has a particular design to increase the efficiency of thepump operation and also to permit inducer means generally designated 63to be added to the impeller as shown in FIG. 18 so as to increase therange of operation of the pump particularly at lower load and at lowerNet Positive Suction Heads (N.P.S.H.) as will now be described.

COMBINDED CASING AND SIDE INLET Thus, referring to FIGS. 10 to 17 of thedrawings, the combined casing and side inlet means 51 shows that theside inlet means section 51b having the connecting fluid flow passage 62is an elongated cylindrical or tubular member having convoluted curvedportions between the inlet 52 and the suction inlet/outlet 56 of thecombined casing and side inlet 51.

It will be noted that the inlet 52 of the combined casing and side inlet51 in assembled position is disposed in a plane above the suctioninlet/outlet 56 and will be in substantial alignment with the dischargeoutlet 53. This construction permits the motor driven centrifugal pump50 to be placed in alignment with the piping (not shown) for the pumpingsystem in which the in line, motor driven centrifugal pump will be used,all of which is clearly shown in FIGS. 10, 11, l2, 13, 14, 15, 16, I7and 18 of the drawings.

Referring to FIG. 1 l, the side inlet means section 51b of the combinedcasing and side inlet means 51 is shown as forming a descending section64, a shaped curved section 65 and a straight cylindrical section 66.These portions are on the side inlet means section 51b, and they containthe corresponding diverging passage section 67, the shaped curvedpassage section 68 and the straight cylindrical passage section 69 ofthe connecting fluid flow passage 62. These passage sections 67, 68 and69 of the connecting fluid flow passage 62 communicates with each otherin the same order as stated from the inlet 52 to the suctioninlet/outlet 56 in the combined casing and side inlet means 51.

Thus, the inlet 52 communicates with the diverging passage section 67which communicates with the shaped curved passage section 68 which inturn communicates with the straight cylindrical passage section 69 incommunication with the suction inlet/outlet 56.

By reference to FIGS. 11, 16 and 17, it can be seen that the suctioninlet/outlet 56 and the straight passage section 69 are in alignmentwith each other and have their centerline on the longitudinal orvertical line of the motor driven centrifugal pump 50.

Further, the suction outlet/inlet 56 and the straight passage section 69are shown as having a diameter D substantially equal to the suction eye61 of the impeller 58 in a same manner as above described for the formof the invention shown in FIGS. 1 to 8 of the drawings.

As in the first form of the invention, this diameter is the referencestandard against which the remaining sections of the connecting fluidflow passage 62 are designed. The diameter D of the outlet/inlet 56however can be greater or less than the diameter of the suction eye 61for impeller 58 by as much as 20%. It will, however, be the referencediameter and not the diameter of the suction eye for the impelleralthough in the preferred embodiment it is considered best to have adiameter substantially the same as the suction eye.

In addition, the straight passage section 69 of the connecting fluidflow passage 62 is shown in FIG. 1 1 as having a predetermined length Bwhich may be a function of the length of inducer means 63 as is shown inFIG. 18 of the drawings.

FIGS. 11, 15 and 16 of the drawings show that the inlet 52 for thecombined casing and side inlet 51 has a diameter A which may be slightlysmaller, equal to or slightly larger than the diameter D of the suctionoutlet- /inlet 56 and generally will be in the ratio between 0.9 to 1.25of the diameter of the suction inlet/outlet 56. The diverging section 67which communicates at one end with the inlet 12 expands to an ovalwindow which has a width CW up to three times the diameter D and aheight CH less than A to provide a total crosssectional area in thepreferred range of approximately 1.75 to 2.00 times the cross-sectionalarea of the suction outlet/inlet 56.

From the point where the shaped curved passage section 68 communicateswith the oval window or opening 70 of the diverging section 67, it iscurved on a radius substantially equal to the diameter D of the suctionoutlet/inlet 56. The radius being drawn on the centerline of thediverging section 67 closest to the inlet side of the straightcylindrical passage section 69 in the same manner as shown in FIG. 7 forthe form of the side inlet means shown in FIGS. 1 to 7 of the drawings.

At the end remote from the oval window 70, the shaped curved section 68narrows to the cylindrical diameter D so that the axial section at thepoint which communicates with the straight cylindrical passage section69 is a smooth uniform and simple bend.

Thus, as in the first form of the invention described there is provideda connecting fluid flow passage from the inlet 52 to the suctionoutlet/inlet 57 which has a specific defined shape for accomplishing theadvantageous and desired results of providing fluid flow at the suctionoutlet/inlet 56 which has a substantially uniform velocity distribution.

It is noted that the preferred dimensional ranges of the form of theinvention shown in FIGS. 10 to 17 are identical with those for the formof the invention shown in FIGS. 1 to 8 of the drawings. It will beunderstood that the general dimensional ranges indicated for the firstform of the invention are equally applicable to this integral casing andside inlet means form of the invention.

Whether the side inlet means is formed as an independent element orintegrally with the casing, it is the shape and design of the fluid flowpassage through the side inlet means that accomplishes the advantageousresults of the present invention, in that it guides and acts on thefluid to be pumped as it passes therethrough so that at the point whenthe fluid to be pumped is delivered into the suction eye of the impellerfor the centrifugal pump, it will have a substantially uniform velocitydistribution.

While the foregoing description illustrates various preferredembodiments in accordance with the present invention, it will beappreciated that certain changes and modifications may be made in thestructure of these disclosed arrangements without departing from thespirit and scope of the invention and that the same is defined by theclaims as hereinafter set forth.

What is claimed is:

1. A side inlet means for centrifugal pumps comprising:

a. first means forming an inlet at one end of the side inlet means,

b. second means formingan outlet at theother end of the side inlet meansand said outlet having a given cross-sectional flow area,

c. means forming a fluid flow passage through said side inlet meansincluding,

1. a descending seciton forming the portion of said fluid flow passagein communication with the inlet, said descending section expanding toprovide at the end of said portion of .the fluid flow passage remotefrom the inlet remote from the inlet end a substantially ellipticalcross-sectional flow area having a major axis and a minor axis and theflow area therethrough being greater than but not more than three timesthe cross-sectional flow area of the outlet,

2. a curved section sized at one end to fit the expanded end of thedescending section, the major axis of the substantially ellipticalcross-sectional flow area being parallel to the axis of curvature ofsaid curved section and the minor axis transverse thereto,

3. said curved section to form the intermediate portion of said fluidflow passage and contracting at the end remote from the end thereofconnected to the descending section to provide at said remote end of theintermediate portion of the fluid flow passage a cross-sectional flowarea substantially equal to the cross-sectional flow area of the outletwhereby the velocity of the fluid flow through the descending sectionis. reduced before it enters the curved section and the velocity of thefluid is accelerated after it leaves the curved section, and

4. a straight cylindrical section between the contracted end of thecurved section and the outlet forming the portion of the fluid flowpassage connecting the intermediate portion with the outlet, and

d. means for connecting the side inlet means into assembled position foruse,

2. A side inlet means for centrifugal pumps comprising:

a. first means forming an inlet at one end of the side inlet means,

b. second means forming an outlet at the other end of the side inletmeans and said outlet having a given cross-sectional flow area,

c. means forming a fluid flow passage through said side inlet meansincluding,

1. a descending section forming the portion of said fluid flow passagein communication with the in let, said descending section expanding atthe end of said portion of the fluid flow passage remote from the inletend,

2. curved section sized at one end to fit the expanded end of thedescending section and forming the intermediate portion of said fluidflow passage,

3. a straight cylindrical section between the end of the curved sectionand the outlet forming the portion of the fluid flow passage connectingthe intermediate portion with the outlet.

d. the cross sectional flow area of the fluid flow passage at the planeof connection bet-ween the descending section and the curved section hasan oval shape and is in a range between 1.75 to 2.0 times thecross-sectional flow area of the outlet for the side inlet means.

e. said curved section contracting at the end remote from the endthereof connected to the descending section to provide at said end ofthe intermediate portion of the fluid flow passage a cross-sectionalflow area substantially equal to the cross-sectional flow area of theoutlet whereby the velocity of the fluid through the descending sectionis reduced before it enters the curved section and the velocity of thefluid is accelerated after it leaves the curved section, and i f. meansfor connecting the side inlet means into assembled position for use.

3. In a side inlet means as claimed in claim 1 wherein,

the curved section is widest at its plane of connection with thedescending section and the intermediate fluid flow passage through thecurved section is formed by an arcuate section,

b. said arcuate section formed on a radius of curvature parallel to avertical plane through the intermediate portion of the fluid flowpassage substantially about the point of intersection of the verticalplane through the intermediate portion with the upper section of theplane of connection between the descending section and curved section,

c. the radius of curvature for said arcuate annular section between 0.9to 1.1 of the diameter of the fluid flow area through the outlet, and

(1. said arcuate section also having a second radius of curvaturesubstantially normal to the vertical plane through the intermediateportion of the fluid flow passage substantially about the point ofintersection of the vertical plane through said intermediate portionwith the centerline of the fluid flow passage at the plane of connectionbetween the descending section and the curved section.

4. In a centrifugal pump,

a. .casing means forming a pumping chamber having a suction inlet ofpredetermine diameter and a discharge outlet,

b. impeller means mounted for rotating in said pumping chamber andhaving a suction eye in communication with the suction inlet for saidcasing,

c. a side inlet means forming a fluid flow passage therein having aninlet at one end and an oulet at the end remote therefrom,

(1. means connecting said side inlet means to said casing whereby theoutlet thereof will be in communication with said suction inlet for thecasing, and said outlet having a given flow area substantially equal tothat of the suction inlet,

e. said side inlet means including,

1. a descending section forming a portion of said fluid flow passage incommunication with the inlet for the side inlet means,

2. said descending section expanding to provide at the end of saidportion of the fluid flow passage remote from the inlet end asubstantially oval cross-sectional flow area having a major axis and aminor axis and the flow area therethrough being greater than but not notmore than three times the cross-sectional flow area of the outlet,

3. a curved section forming the intermediate portion of said fluid flowpassage sized and shaped at one end to connect to the expanded end ofthe descending section so that the major axis of the ovalcross-sectional flow area is parallel to the axis of curvature of saidcurved section and the minor axis normal thereto,

4. said curved section contracting at the end remote from the endthereof connected to the descending section to provide at said end ofthe intermediate portion of the fluid flow passage a cross-sectionalflow area substantially equal to the cross-sectional flow area of theoutlet whereby the velocity of the fluid flowing through the descendingsection is reduced before it enters the curved section and the velocityof the fluid is accelerated as it leaves the curved section, and

5. a straight cylindrical section connected between the end of thecurved section remote from the descending section and the outlet for theside inlet means to form the portion of the fluid flow passageconnecting the intermediate portion with the outlet to deliver fluid atsubstantially uniform average velocity into the suction eye of theimpeller.

5. In a centrifugal pump,

a. casing means forming a pumping chamber having a suction inlet ofpredetermined diameter and a discharge outlet,

b. impeller means mounted for rotation in said pumping chamber andhaving a suction eye in communication with the suction inlet for saidcasing.

c. a side inlet means forming a fluid flow passage therein having aninlet at one end and an outlet at the end remote therefrom,

(1. means connecting said side inlet means to said casing whereby theoutlet thereof will be in communication with said suction inlet for thecasing, and said outlet having a given flow area substantially equal tothat of the suction inlet,

e. said side inlet means including,

l. a descending section forming a portion of said flow passage incommunication with the inlet for the side inlet means,

2. said descending section expanding to provide at the end of saidportion of the fluid flow passage remote from the inlet end an ovalcross-sectional flow area,

3. a curved section sized and shaped at one end to connect to theexpanded end of the descending section and forming the intermediateportion of said fluid flow passage,

4. a straight cylindrical section connected between the end of thecurved section remote from the descending section and the outlet for theside inlet means to form the portion of the fluid flow passageconnecting the intermediate portion with the outlet to deliver fluid atsubstantially uniform average velocity into the suction eye of theimpellor,

f. the cross sectional flow area of the flulid flow passage at the planeof connection between the descending section and the curved section isin a range between 1.75 to 2.0 times the cross-sectional flow area ofthe outlet for the side inlet means, and

g. said curved section contracting at the end remote from the endthereof connected to the descending section to provide at said end ofthe intermediate portion of the fluid flow passage a cross-sectionalflow area substantially equal to the cross-sectional flow area of theoutlet whereby the velocity of the fluid flowing through the descendingsection is reduced before it enters the curved section and the velocityof the fluid is accelerated as it leaves the curved section.

6. In a centrifugal pump as claimed in claim 4 wherein,

a. said centrifugal pump includes inducer means,

b. said straight cylindrical passage section having a predeterminedlength and a cross-sectional flow area substantially equal to saidoutlet for the side inlet means to permit the inducer means for saidcentrifugal pump to extend in the centerline thereof at least a portionof the length of said cylindrical section.

1. A side inlet means for centrifugal pumps comprising: a. first meansforming an inlet at one end of the side inlet means, b. second meansforming an outlet at the other end of the side inlet means and saidoutlet having a given cross-sectional flow area, c. means forming afluid flow passage through said side inlet means including,
 1. adescending seciton forming the portion of said fluid flow passage incommunication with the inlet, said descending section expanding toprovide at the end of said portion of the fluid flow passage remote fromthe inlet remote from the inlet end a substantially ellipticalcross-sectional flow area having a major axis and a minor axis and theflow area therethrough being greater than but not more than three timesthe cross-sectional flow area of the outlet,
 2. a curved section sizedat one end to fit the expanded end of the descending section, the majoraxis of the substantially elliptical cross-sectional flow area beingparallel to the axis of curvature of said curved section and the minoraxis transverse thereto,
 3. said curved section to form the intermediateportion of said fluid flow passage and contracting at the end remotefrom the end thereof connected to the descending section to provide atsaid remote end of the intermediate portion of the fluid flow passage across-sectional flow area substantially equal to the cross-sectionalflow area of the outlet whereby the velocity of the fluid flow throughthe descending section is reduced before it enters the curved sectionand the velocity of the fluid is accelerated after it leaves the curvedsection, and
 4. a straight cylindrical section between the contractedend of the curved section and the outlet forming the portion of thefluid flow passage connecting the intermediate portion with the outlet,and d. means for connecting the side inlet means into assembled positionfor use.
 2. said descending section expanding to provide at the end ofsaid portion of the fluid flow passage remote from the inlet end asubstantially oval cross-sectional flow area having a major axis and aminor axis and the flow area therethrough being greater than but not notmore than three times the cross-sectional flow area of the outlet, 2.said descending section expanding to provide at the end of said portionof the fluid flow passage remote from the inlet end an ovalcross-sectional flow area,
 2. a curved section sized at one end to fitthe expanded end of the descending section, the major axis of thesubstantially elliptical cross-sectional flow area being parallel to theaxis of curvature of said curved section and the minor axis transversethereto,
 2. A side inlet means for centrifugal pumps comprising: a.first means forming an inlet at one end of the side inlet means, b.second means forming an outlet at the other end of the side inlet meansand said outlet having a given cross-sectional flow area, c. meansforming a fluid flow passage through said side inlet means including, 2.curved section sized at one end to fit the expanded end of thedescending section and forming the intermediate portion of said fluidflow passage,
 3. a straight cylindrical section between the end of thecurved section and the outlet forming the portion of the fluid flowpassage connecting the intermediate portion with the outlet. d. thecross sectional flow area of the fluid flow passage at the plane ofconnection between the descending section and the curved section has anoval shape and is in a range between 1.75 to 2.0 times thecross-sectional flow area of the outlet for the side inlet means. e.said curved section contracting at the end remote from the end thereofconnected to the descending section to provide at said end of theintermediate portion of the fluid Flow passage a cross-sectional flowarea substantially equal to the cross-sectional flow area of the outletwhereby the velocity of the fluid through the descending section isreduced before it enters the curved section and the velocity of thefluid is accelerated after it leaves the curved section, and f. meansfor connecting the side inlet means into assembled position for use. 3.said curved section to form the intermediate portion of said fluid flowpassage and contracting at the end remote from the end thereof connectedto the descending section to provide at said remote end of theintermediate portion of the fluid flow passage a cross-sectional flowarea substantially equal to the cross-sectional flow area of the outletwhereby the velocity of the fluid flow through the descending section isreduced before it enters the curved section and the velocity of thefluid is accelerated after it leaves the curved section, and
 3. a curvedsection sized and shaped at one end to connect to the expanded end ofthe descending section and forming the intermediate portion of saidfluid flow passage,
 3. a curved section forming the intermediate portionof said fluid flow passage sized and shaped at one end to connect to theexpanded end of the descending section so that the major axis of theoval cross-sectional flow area is parallel to the axis of curvature ofsaid curved section and the minor axis normal thereto,
 3. In a sideinlet means as claimed in claim 1 wherein, the curved section is widestat its plane of connection with the descending section and theintermediate fluid flow passage through the curved section is formed byan arcuate section, b. said arcuate section formed on a radius ofcurvature parallel to a vertical plane through the intermediate portionof the fluid flow passage substantially about the point of intersectionof the vertical plane through the intermediate portion with the uppersection of the plane of connection between the descending section andcurved section, c. the radius of curvature for said arcuate annularsection between 0.9 to 1.1 of the diameter of the fluid flow areathrough the outlet, and d. said arcuate section also having a secondradius of curvature substantially normal to the vertical plane throughthe intermediate portion of the fluid flow passage substantially aboutthe point of intersection of the vertical plane through saidintermediate portion with the centerline of the fluid flow passage atthe plane of connection between the descending section and the curvedsection.
 4. said curved section contracting at the end remote from theend thereof connected to the descending section to provide at said endof the intermediate portion of the fluid flow passage a cross-sectionalflow area substantially equal to the cross-sectional flow area of theoutlet whereby the velocity of the fluid flowing through the descendingsection is reduced before it enters the curved section and the velocityof the fluid is accelerated as it leaves the curved section, and
 4. In acentrifugal pump, a. casing means forming a pumping chamber having asuction inlet of predetermine diameter and a discharge outlet, b.impeller means mounted for rotating in said pumping chamber and having asuction eye in communication with the suction inlet for said casing, c.a side inlet means forming a fluid flow passage therein having an inletat one end and an oulet at the end remote therefrom, d. means connectingsaid side inlet means to said casing whereby the outlet thereof will bein communication with said suction inlet for the casing, and said outlethaving a given flow area substantially equal to that of the suctioninlet, e. said side inlet means including,
 4. a straight cylindricalsection connected between the end of the curved section remote from thedescending section and the outlet for the side inlet means to form theportion of the fluid flow passage connecting the intermediate portionwith the outlet to deliver fluid at substantially uniform averagevelocity into the suction eye of the impellor, f. the cross sectionalflow area of the flulid flow passage at the plane of connection betweenthe descending section and the curved section is in a range between 1.75to 2.0 times the cross-sectional flow area of the outlet for the sideinlet means, and g. said curved section contracting at the end remotefrom the end thereof connected to the descending section to provide atsaid end of the intermediate portion of the fluid flow passage across-sectional flow area substantially equal to the cross-sectionalflow area of the outlet whereby the velocity of the fluid flowingthrough the descending section is reduced before it enters the curvedsection and the velocity of the fluid is accelerated as it leaves thecurved section.
 4. a straight cylindrical section between the contractedend of the curved section and the outlet forming the portion of thefluid flow passage connecting the intermediate portion with the outlet,and d. means for connecting the side inlet means into assembled positionfor use.
 5. a straight cylindrical section connected between the end ofthe curved section remote from the descending section and the outlet forthe side inlet means to form the portion of the fluid flow passageconnecting the intermediate portion with the outlet to deliver fluid atsubstantially uniform average velocity into the suction eye of theimpeller.
 5. In a centrifugal pump, a. casing means forming a pumpingchamber having a suction inlet of predetermined diameter and a dischargeoutlet, b. impeller means mounted for rotation in said pumping chamberand having a suction eye in communication with the suction inlet forsaid casing. c. a side inlet means forming a fluid flow passage thereinhaving an inlet at one end and an outlet at the end remote therefrom, d.means connecting said side inlet means to said casing whereby the outletthereof will be in communication with said suction inlet for the casing,and said outlet having a given flow area substantially equal to that ofthe suction inlet, e. said side inlet means including,
 6. In acentrifugal pump as claimed in claim 4 wherein, a. said centrifugal pumpincludes inducer means, b. said straight cylindrical passage sectionhaving a predetermined length and a cross-sectional flow areasubstantially equal to said outlet for the side inlet means to permitthe inducer means for said centrifugal pump to extend in the centerlinethereof at least a portion of the length of said cylindrical section.